#!/usr/bin/env node
 
const stdin = process.stdin,
      stdout = process.stdout;
stdin.on('data',(data)=>{
 stdout.write( data.toString('utf8').toUpperCase());
});
stdin.push('hello');
stdin.push('world');
for(let c = 'a'.charCodeAt(0);c<='z'.charCodeAt(0);c++){
  stdin.push(String.fromCharCode(c));
}
stdin.push(null);

//输入流结束
//可读流有pipe()
stdin.pipe(stdout);

